Electronic Eyebox Expansion via Dynamic Exit Pupil Tracking
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Solution Overview
Problem
Magnified telescopic sights face challenges with small exit pupil sizes, leading to stability issues and vignetting due to the fundamental principles of geometric optics, which result in large, heavy, and expensive optics when trying to achieve a larger eyebox.
Innovation Solution
An optical imaging device with a front optics system, an optical deflector unit, an infrared illuminator, an eye-shift sensor, and a digital image processor that tracks the operator's eye movements to automatically adjust the exit pupil's position, effectively creating a larger electronic eyebox without increasing the size or weight of the optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the exit pupil diameter is increased to enlarge the eyebox, then the ease of operation is improved, but the entrance pupil diameter and device length must be significantly increased according to geometric optics principles
Solution Approach 1:
The patent employs a movable field lens that can be dynamically repositioned along the optical axis and laterally to adjust the exit pupil location. This dynamic adjustment allows the eyebox to be enlarged without changing the physical dimensions of the telescope body, resolving the contradiction between ease of operation and device length
Solution Approach 2:
The system changes the positional parameters of the field lens and exit pupil to achieve a larger effective eyebox. By varying the field lens position and the exit pupil location relative to the eyepiece, the system enlarges the eyebox without increasing the entrance pupil diameter or device length
2Ease of operation
If the exit pupil diameter is increased to enlarge the eyebox, then the ease of operation is improved, but the device weight increases due to larger optics
Solution Approach 1:
The movable field lens mechanism allows dynamic repositioning of the exit pupil to create a larger eyebox without requiring larger or heavier optical elements. The existing optics remain the same size, and only the field lens position is adjusted, thus improving ease of operation without increasing device weight
3Ease of operation
If the exit pupil diameter is increased to enlarge the eyebox, then the ease of operation is improved, but the device complexity and cost increase
Solution Approach 1:
The patent introduces a dynamically adjustable field lens mechanism that can be repositioned to change the exit pupil location. This adds controlled complexity to the optical system, but the complexity is localized to a single adjustable element rather than requiring a complete redesign of the entire optical train, thus improving ease of operation with manageable device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for a stable and clear field of view without vignetting, even with head or hand movements, by dynamically repositioning the exit pupil to match the eye's position, thus enhancing usability without altering the original optical parameters.
Implementation Method 1
an infrared illuminator unit configured to project infrared electromagnetic radiation onto an eye of an operator of the optical imaging device
Implementation Method 2
an eye-shift sensor unit configured to produce an image of the eye illuminated by said infrared illuminator unit, the image of the eye including a spot representative of the exit pupil
Implementation Method 3
The optical deflector unit is coupled to the digital image processor unit, and is configured to receive the feedback data from the digital image processor unit, and to decenter the field lens in two orthogonal axes relative to an optical axis of the optical imaging device to relocate the exit pupil of the optical imaging device responsive to the feedback data
Data Source
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AI summary
Methods and apparatus for automatically expanding the eyebox of an optical imaging device by tracking the movement of an operator's eye, and automatically repositioning the exit pupil of the optical imaging device to follow the movement of the eye.